Interpolation methods and splice options for three-dimensional transport calculations using PARTISN

A three-dimensional splice option has been developed for the discrete ordinates transport code PARTISN. The splice option can be used to permit changes in angular quadrature and spatial mesh at user-defined splice plane boundaries, allowing for complicated transport problems to be broken into smaller, more manageable pieces. Splice techniques can be used to decrease computational run-time and as a sensitivity analysis tool in system design to study affects of material changes in small subregions of interest. The splice techniques require both angular and spatial interpolation methods at the splice plane boundaries. The angular interpolation method involves a combination of spherical harmonic expansions and least squares algorithms. A bilinear spatial interpolation of the flux is used for changes in spatial discretization at the splice planes. Both interpolation methods are discussed and features of the splice capabilities are given. (authors)